This is a draft of the next post. It covers general Fusion. Feedback Appreciated.

Introduction:

On March seventeenth, General Fusion spoke at TED largest conference [46]. You can watch the talk here. Its founder, Michel Laberge has been in fusion for twelve years. He has earned this recognition. The company started as his kooky idea. He has some cash, a PhD and a mid-life crisis. Over time, it has moved down a typical entrepreneurial path (by contrast, EMC2 and LPP have not). Board seats were first given to investors; and then later, to energy industry veterans [35]. This was needed to secure 55 million funding, get mainstream press and to hire the sixty employees [1]. But, the cash comes with strings. If successful - the VC firms will reap the winnings. The company has also been publishing: four papers last year [3-6]. Blogger Henning Dekant recently got a look at their labs [2]. He described it as: “…an engineering approach to fusion and [we] are in a hurry…” Good. We need to hurry.

Overview:

Michels’ first paper explains the idea simply [34]. It uses a liquid lead-lithium wall. This moves around a spherical cavity. Pumps spin the metal along the equator and draw it off at the poles. This forms a vacuum cavity. Deuterium and tritium is shot into this cavity [36]. This is done with a toroid. It is then compressed by a pressure wave. The cavity reaches fusion condition. If fusion happens, the liquid metal absorbs any products. The liquid metal then exchanges heat with steam. This turns turbines, making electrical power.

On paper, I like this idea. Riders’ thesis tells us that hot, uniform plasma with a bell curve of energy – is a bad direction to go in. This design goes in the opposing direction. It heats the plasma. It spins the plasma. It squeezes the plasma. It combines several old fusion ideas: a liquid wall, a closed magnetic field and compression [40]. Ken Fowler, fusion great, loved this idea [36]. On paper, it looks fine.

Details:

We modeled their prototype. This is working, now [46, 45]. The model is rough. Ballpark values were used: this is in design phase so that is fine. Numbers will continue to vary – between tests, targets and what is affordable. The machine has a one meter sphere. Fourteen pistons surround this chamber. They are steam driven. They hit a steel anvil; not the lead itself. This is illustrated below. The outside (a sixteen sided polyhedron) was estimated from pictures.

The chamber is filled with a lead (99.3%) and lithium (0.7%) mixture. This is at 400 Celsius and a density of 10,000 kilogram per cubic meter [38, 39, 6]. It is spun at a few meters per second [47], around a forty centimeter cavity [37]. The cavity maybe evacuated, filled with air or argon [XXX]. Control over spinning really gives them an edge over ICF. It controls their target, simplifying it. This may help with the Rayleigh–Taylor instability.

The Wave:

The compression can be modeled in three parts. First, is the pressure made by a single piston. The piston is fired. It speeds up towards a steel anvil. It hits. The wave is made. The anvil wiggles – moving the wave directly into the liquid lead [40]. An illustration of this impact is shown below [37, 40, 6].

Next, the wave jumps from anvil to the lead. In the process, it loses nine percent of its energy [40]. What happens next, is not fully understood. In the lead, waves move inward. The liquids’ spinning motion may effect this. Waves diffract with other waves - like ripples on water. Mach waves can also form within this diffraction [37]. Additionally, the lead was already pressurized [6]. They focus into the center, and crush the cavity. Before the crush, spinning plasma is injected. The cavity squeezes down to one tenth the size [XXX]. Ideally, this initiates fusion.

Compression Analysis:

The compression is both complex and critical. General Fusion first used a masters’ student to model it [37]. Later, a physicist was hired to do the same job [4, 5, 6]. To simplify the “anvil-wall-lead” system, a cheap finite element software was used [44]. This simplified the wave. The pressure modeled for one piston, is shown below.

This was input for a second software. It was a boundary condition for a CFD code. They used an open-source code for this [42]. Free software; it shows how frugal this team is. The computer looked at two cases. First was a collapsing 2D wave. Next was the same scenario in three dimensions. One result is shown below [6].

Like a wave crashing on a beach. The pressure moves from outside, inward. Waves combine; increasing in power. The energy occupies less space, leading to “geometric focusing”. In half a millisecond, the wave doubles in strength. Ideally, this compresses the plasma in the center, leading to fusion.

Northwest Nuclear Consortium

Introduction:

Carl Greninger is a very passionate guy. His first passion is education; and he is not happy with the trends. He points to a high school dropout rate - in his state - of 24% [7]. Deeper still: Carl is upset that schools are not getting kids excited about science. The kids “…were not impressed, I suddenly saw that while we may be teaching the curriculum - if we’re not inspiring, if we’re not creating passion, then it is a waste of time…” [8]. Fed-up with this, Carl decided to act. He started the northwest nuclear consortium in 2010 [9]. This group is: “the only nuclear engineering curriculum for public high school students in the U.S. with a working fusion reactor” [10]. Each week, a group of students and instructors meet to do nuclear fusion at Mr. Greningers’ home [12].

Standoffish parents - have rapidly become noisy supporters of NWNC. Their kids have collectively won $410,000 in college scholarships [9]. Wow. They are crushing science fairs. They won 2nd place in physics, at the Intel International Science and Engineering Fair beating out millions of other entries [11]. They have also won state, and local competitions [12, 43]. There are four projects/teams listed [13]:

1.Safety Team. A team monitors doses, metals, shielding and personal protection. Unconvinced neighbors called the Office of Radiation Protection [14]. They sent Mike Brennan, a radiation health physicist. Mike declared: “I think that it is not only safe, but he is teaching safety [creating] a culture of safety…”

2.An ion accelerator. This tool speeds ions down a negative 240K voltage. The potential is made using an AC to DC voltage multiplier. The resulting ion beam will add to the groups’ capabilities.

3.Anisotropic fusion. With fusion, come neutrons. Their release is not well understood. A team covered a wall with detectors, charting the neutrons [43]. Results showed most fusion occurring when ions hit the cage, not each other.